Vision RAG for Scanned PDFs 2026: ColPali & Qdrant Guide
Vision RAG with ColPali replaces brittle OCR for scanned PDFs: build a ColQwen and Qdrant retrieval pipeline in 2026 that reads layout, tables, and...
Chapter 1: Why OCR Is the Bottleneck: The 2026 Scanned-PDF Problem Every retrieval-augmented generation demo you have seen works beautifully. Someone drops a clean, digitally-born PDF into a chunker, embeds the chunks, and asks a question. The answer comes back correct and cited. Then you point that same pipeline at your company's actual document store — a decade of scanned invoices, contract addenda with handwritten margin notes, engineering drawings, government forms, and pages that were photocopied so many times the letters have started to dissolve — and accuracy falls off a cliff. The failure is not in your embedding model....